This invention relates to means for mounting a sprocket drum for driving a scraper assembly of a scraper-chain conveyor, and to a drive arrangement for such a scraper assembly. In particular, the invention is concerned with the lubrication of sprocket drum mounting means.
Scraper-chain conveyors are used in mine workings for removing won mineral material (such as coal) from the face area. The scraper assembly of such a conveyor is driven by a sprocket drum mounted in a drive frame at one end of the conveyor. A similar sprocket drum and drive frame is provided at the other end of the conveyor, and this second sprocket drum can form part of an auxiliary drive or be an idler sprocket drum. The drive motor and gearing for a driven sprocket drum is attached to the associated drive frame by flanging.
In order to seal the annular gaps between the end faces of a sprocket drum and the adjacent stationary members (such as the side plates of the drive frame), use is made of slide ring seals. A slide ring seal (or "lifetime" seal) has a pair of relatively-rotatable, contacting metal rings which are held in sealing and sliding contact by resilient rings. In order to lubricate such a seal, the seal space surrounding the seal is connected to the bearing space surrounding an adjacent roller bearing which is used for rotatably supporting the sprocket drum in the drive frame. Lubricant can, therefore, be forced into the seal space via the bearing space. In this arrangement, the bearing space is provided with a lubricant supply passage and a lubricant discharge passage, the lubricant discharge passage leading directly away from the bearing space. Thus, a closed-circuit lubricant path is formed by the lubricant supply passage, the bearing space and the lubricant discharge passage, so that fresh lubricant supplied via the lubricant supply passage flushes out old lubricant from the bearing via the lubricant discharge passage. Unfortunately, the seal space is supplied with lubricant via a "dead-end" branch passage leading from the bearing space, so that fresh lubricant cannot be supplied to the seal. (See DE-OS No. 2 327 852).